Instrument structure



Oct. 2, 1192s.

P. M GAHAN 1,6855951 INSTRUMENT STRUCTURE Filed July 17, 1926 WITNESSES: INVENTOR PaU/fiacfiahan ATTORNEY Patented Oct. 2, 1928.

U STATES P NT O FIC PAUL MAGGAHAN', OF'ORANGE,'1\TE\V J ERSEYQASSIGNOR TO WESTINGHOUSE ELECTRIC 7 i &. MANUFACTURING COMPANY, A CORPQRATI ON F EENNSYLVANIA.-

,DTSTRUMENTSTRUCTURE. i

; Application filed July 17, 1926. Serial no. 123,204.

tures and particularly to means for supporting the movable elements of indicating meters of the Darsonval type.

1 'One object of my invention is to provide "means, o'f the above indicated character,

, that shall reduce the likelihood of damage to the instrument from shocks and jars.

Another object of my invention is to, increase the surface-creepage distance between partsof unlike potential in Darsonval instruments s r 'Another object of my invention is to reduce the number of parts usually required "in instruments of theabove-indicated character to thereby eifect' economy of construction and to facilitatetheassembly of the instruments. Q A'further object ofmy invention is to provide a Darsonval instrument that shall be simple and durable in construction and effective in operation. j 7

In Darsonval' instruments of a certain -"construction, it has heretofore been usual to support the movable coils or elements between the poles ofpermanent magnets by means of metalbridge'members that are supported, adjacent to the ends thereof, by metal standards from whichthe bridges are insulated by small insulating washers or bushings.

These small parts are not only difficult to handle in assembling the instruments-but also afford only a relatively small surface creepage distance between the bridges and standards.

I propose to overcome the above-mentioned objections and to provide a materi-- ally improved instrument of fewer parts, more economical construction, better insulating characteristics, easier assembly and more eifective operation and one which is less likely to be damagedby rough usage.

Accordingly, in practicing my invention,

. I so construct the bridge member or members entirely of insulating material as to permit them to severally take the places of two or more small parts heretofore used and to provide the other advantages above-mentioned.

Figure 1 of the accompanying drawings, is a side elevational view of a portion of a vention, and

Darsonval instrument embodying my inl Fig'. 2 is a bottom plan view of the instrument shown in Fig. 1.

The device comprises, in general, a permane'nt' 'field' magnet 1, pole, members 2 therefor, a stationary cylindrical core member 3 disposed between the pole members 2,

a movable element or coil 5 surrounding the core member 3, a pointer 6 carried by the coil 5, non-magnetic bridge members 7 secured to the magnet 1 by'bolts 8 for supporting the stationary core 3, insulating bridge members 10 carrying bearing members '11 for, the coil .5, and standards 12 for supporting the bridge members 10.

inverted U-shape and of rectangular cross sectional area having plane inner surfaces against which corresponding surfaces on the pole members 2 rest. The pole members 2, which are suitably secured in position-between" the freeends of the magnet 1, are provided with inner or pole surfaces of cylindrical curvature and of sufficiently greater radius than thecylindrical core 3 'to provide cylindrical spaces in which the sides of: the coil 5 are adapted to turn.

Y The core 3 is supported, adjacent to-"its ends, by the non-magnetic bridge members 7 in a specific manner not germane to this invention, and the latterare provided with arcuate slots 14:, registering with the spaces held in position by nuts 17.

The standards 12 are of any suitable construction and may consist of metal sleeves through which screws 18 extend. The latter, which also serve to mount the insulating bridges 10, may further extend into the pole members 2.

The bridge members 10 are preferably con? 1e permanent magnetl is preferably of structed as punchings of relatively thin sheet mica-rta or other suitable insulating material having enlarged apertured discoidal end portions for the reception of the screws l8 and similar central portions for the reception of the bearin screws 11.

r In a usual instrument 0 this character, in which the bridge members 10 are of metal, it is necessary to provide inst-11mm between the bridges and. the screws 18. This insulation, adjacent to each screw, may be in the form of a washer and a flanged Meshing, a sleeve and two washersor may be otherwise constructed.

Whatever may be the manner of so providing this insulation", it involves small parts which are difficult to handle, which provide I 1 very little surface-creepage distance" between the bridge and the standards, and which are relatively expensive, as compared to the de- Vice of my invention. g Being of insulating material, thebrid'ge members I0 are ofa damped yi'el dable nature' which cushion the forces of shocks and jars tothe instrument and thereby prevent damage to the delicate moving; parts and bearings. I 7

While I have shown and described a particular" form oi my invention, changes may be e'fiected' therein without departing from the spirit and scope thereof, as indicatedby the a pendediclairns;

I claim'as my invention a 1". In an in trumenathe; combination with a fi'eldqnagnet structure embodying" spaced cooperating pole portions and a mov-abl e element disposedbetween said portions, of bridge structure of insulating material extending transversely to the axis of" said element for suppm-ting the same in position.

i 2.; In an instrument the combination with a field'magnetstructure embodying spaced cooperating? poleportiens and a movable element dispose'd betweensaid portions, of bridge structure at insulating material ea:-

tending: transversely to the" axis of staid old-- ment for sal'pporting'. the" same in" position,

and portions extending from said field-magnet structure substantially parallel to said axis adjacent to the ends of said bridge for supporting 'the same,

4; In an instrument, tlie' combination with a field-magnet structure embt' ing spaced cooperating pele; portions an r amenable e element disposed between said portions, of

ab idge member" at insiilatin' material ex:

tending'transversely to the axis of s id element acent to each end thereof orsupporting the same in osition, and ortifons extending from said field-magne s mete-re substantialiy parallel to said axis adjaceia to the ends of the bridge members fer sup- POL-U111 the same. v

5. Tile combination with a" steering ssam comprising magn tic; it -central ed structure, of members ofinsmatingmaterial disposed transversely of said structure and on which said deflecting systeiii is" pivoted,

and means for supporting said insulatin i member-sin spaced relation;

o. The combination with a dflectingis tem comprising magnetic-fux cont'roled structure, orme'inte s or phen li dndtnsation material disposed tr ansveisely 9 said structure and on which said deflecting system is pivoted, and means for? supporting said members in spacedrelation.

In testimonywhereof -el have hereunto subscribed my name this 8th day 1926. 

